The present invention relates to a portable electronic apparatus, and more particularly to a portable telephone whose ringing tone can be adjustable in volume.
According to the prior art, a portable telephone, which is a sort of portable electronic apparatus, is annoying at night if its ringing tone is set too loud, sometimes even so loud as to awaken sleeping persons. To prevent this nuisance, the ringing tone volume is adjusted based on the ambient lightness, as described in the Gazette of the Utility Model Laid-open No. 1988-185332.
More specifically, such a portable telephone is provided with a ringing tone generator, selector switches, a controller, a light meter, a volume control knob and a bell. When the controller is selected by the selector switches, the controller adjusts the volume of the ringing tone according to the light level detected by the light meter.
In this case, the turning of the selector switches to the controller side by the user of the telephone causes the controller to reduce the ringing tone volume when the ambience is dark, such as during the user's sleeping hours, and thereby to prevent the tone from being too loud at night and from awakening the user of the telephone or anyone else nearby.
However, the conventional telephone described above, because its ringing tone volume is reduced when its light meter detects the ambient darkness, has the disadvantage that the ringing tone is hardly audible if the portable telephone, with its selector switches kept turned to the controller side, is put into the user's bag or the like.
Furthermore, even if the telephone is put into a bag with its selector switches turned to the volume control knob side, if the ringing tone volume is set with the volume control knob loud enough to be audible from within the bag, the tone would be so loud, when the portable telephone is taken out of the bag, as to annoy the people nearby.